17 hours to get all 120 stars with mario...less with the other secret character.

I think I have around 80 stars...I think that 30 hours would be a good minimum for getting all of them. There's a few of them that will feel like they take hours (Sweet Sweet Galaxy, anyone?), which is really all that matters--you will definitely get your money's worth out of this game.

FOREVER!!

I only get to play it like 6-7 hours a week since I have work and I run a guild in world of warcraft so not much time for it. I usually make time for it after midnight and play for about 30 minutes since I have to get up by 6am.

So far i have 40 stars and I have been completing EVERY stage without skipping, not too shabby me thinks :-)

On a different subject i'm so backed up with games, I bought these but haven't played them yet: Manhunt 2, Silent Hill Origins, Tomb Raider Anniversary, Resident Evil 4, Resident Evil Umbrella Chronicles, Zelda Twilight, Zelda DS, Naruto DS, Phoenix Wright, Assassin's Creed and Call of Duty 4....I'll have to quit my job soon.

The average is about 15 hours.